<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>v-if</title>
</head>
<body>
    <div id="app">
        <input type="button" value="切换显示状态" @click="toggleIsShow">
        <p v-if="isShow">显示内容</p><!-- 操作dom元素（添加或者删除） -->
        <p v-if="temperature>=40">热</p>
    </div>
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
    <script>
        var app=new Vue({
            el:"#app",
            data:{
                isShow:"false",
                temperature:40
            },
            methods:{
                toggleIsShow:function(){
                    this.isShow=!this.isShow
                }
            }
        })
    </script>
</body>
</html>